Background: Increasing levels of artificial light at night (ALAN) and urbanization are becoming prevalent drivers of global insect declines. A key cause of this is that insects fly towards artificial lights (a behavior known as flight-to-light), leading to exhaustion, decreased foraging and reproduction, and increased vulnerability to predation. Shedding light on the environmental determinants of the timing of insect flight-to-light behavior carries implications for the conservation of at-risk species in increasingly illuminated urban, suburban, and rural habitats alike.